Announcing ncurses 6.1

The ncurses (new curses)
library is a free software emulation of curses in System V
Release 4.0 (SVr4), and more. It uses terminfo format, supports
pads and color and multiple highlights and forms characters and
function-key mapping, and has all the other SVr4-curses
enhancements over BSD curses. SVr4 curses became the basis of
X/Open Curses.

In mid-June 1995, the maintainer of 4.4BSD curses declared
that he considered 4.4BSD curses obsolete, and encouraged the
keepers of unix releases such as
BSD/OS, FreeBSD and NetBSD to switch over to ncurses.

Since 1995, ncurses has been
ported to many systems:

It is used in almost every system based on the Linux kernel
(aside from some embedded applications).

It is used as the system curses library on OpenBSD, FreeBSD
and OSX.

It is used in environments such as Cygwin and MinGW. The
first of these was EMX on OS/2 Warp.

It is used (though usually not as the system
curses) on all of the vendor unix systems, e.g., AIX, HP-UX, IRIX64, SCO,
Solaris, Tru64.

It should work readily on any ANSI/POSIX-conforming
unix.

The distribution includes the library and support utilities,
including

This release is designed to be source-compatible with
ncurses 5.0 through 6.0; providing
extensions to the application binary interface (ABI). Although
the source can still be configured to support the ncurses 5 ABI, the intent of the release is to
provide extensions to the ncurses6 ABI:

improve integration of tput
and tset

provide support for extended numeric capabilities.

There are, of course, numerous other improvements, listed in
this announcement.

The release notes also mention some bug-fixes, but are focused
on new features and improvements to existing features since
ncurses 6.0 release.

The improved integration of tput and tset
made only small changes to the libraries. However, supporting
extended numeric capabilities required a few changes:

The TERMINAL structure in
<term.h> is now opaque. Doing that allowed
making the structure larger, to hold the extended numeric
data.

A few applications required changes during development of
ncurses 6.1 because those
applications misused the members of that structure, e.g.,
directly modifying it rather than using
def_prog_mode.

Having made TERMINAL opaque (and because none
of the library functions use anything except a pointer to
TERMINAL), it was possible to increase the size
of the structure, adding to the end.

Existing applications which were linked to the
ncurses 6.0 high-level
(ncurses, ncursesw) and low-level
(tinfo, tinfo) libraries should not require
re-linking since the binary interface did not change, nor did
the structure offsets with TERMINAL change.

A few applications use the inner TERMTYPE
structure's offsets to refer to terminfo capabilities within
that structure. Again, those do not require modification
because their offsets within TERMINAL did not
change.

When configured for wide-characters, i.e.,
“ncursesw” the TERMINAL structure is
extended.

The new data in TERMINAL holds the same
information as TERMTYPE, but with larger numbers
(“int” versus “short”). It is named
TERMTYPE2.

The library uses this structure internally in preference
to TERMTYPE, referring to TERMTYPE
only to initialize it for applications that use the
capabilities defined in <term.h>

When configured for 8-bit (narrow) characters, the
TERMTYPE2 structure is not used.

The updated application binary interface is 6.1.20171230
(used for new versioned
symbols), although the interface changes were developed
several months previously.

The motivation for making this extension came from noticing
that
termcap applications could (though not
realistically) use larger numbers than would fit in 16-bits,
and the fact that the number of color pairs for a 256-color xterm
could not be expressed in terminfo (i.e., 32767 versus 65536).
Also, a few terminals support direct-colors, which could use the
extension.

Generally speaking, applications that use internal details of
a library are unsupported. There was exactly one exception for
ncurses: the tack program used the internal
details of TERMINAL, because it provides an
ncurses-specific feature for interactively modifying a terminfo
description and writing the updated description to a text-file.
It was possible to not only separate tack from these internal
details of ncurses, but to
generalize it so that the program works with Unix curses
(omitting the ncurses-specific feature). That was released as
tack 1.08 in July
2017.

While making changes to tack to
eliminate its dependency upon ncurses internals, the publicly-visible
details of those internals were reviewed, and some symbols were
moved to private header files, while others were marked
explicitly as ncurses internals.
Future releases of ncurses may
eliminate some of those symbols (such as those used by
tack 1.07) because they are
neither part of the API or the ABI.

Using the TERMTYPE2 extended numeric
capabilities, it is possible to support both color pair values
and color values past 32767. Taking compatibility into account,
developers readily understand that neither function signatures
nor structure offsets change. Also, existing functions have to
operate with the extended numbers. Most of that work is internal
to the library. For the external interfaces, a hybrid approach
was used:

X/Open Curses defined function prototypes such as
wattr_set with an unused parameter, for
“future” use. After 25 years, the future is here:
ncurses uses the parameter to
augment color pair values as described in the
manual page.

Other functions such as those defining color pairs did not
have a corresponding reserved parameter. For those,
ncurses defines extended
versions such as init_extended_pair (versus
init_pair), init_extended_color
(versus init_color).

Additionally, to improve performance other changes (and
extensions) are provided in this release:

Several new functions simplify management of large sets of
color pairs: reset_color_pairs,
alloc_pair, find_pair and
free_pair.

New "RGB" extension capability for direct-color support is
used to improve performance of
color_content.

The internal colorpair_t is now a struct,
eliminating an internal 8-bit limit on colors

Allocation for SCREEN's color-pair table
starts small, grows on demand up to the limit given in the
terminal description.

modify logic for endwin-state to be able to
detect the case where the screen was never initialized, using
that to trigger a flush of ncurses' buffer for mvcur,
e.g., in the sample program dots_mvcur for the term-driver
configuration.

These are corrections to existing features:

fixes for writing extended color pairs in
putwin.

modify no-leaks code for lib_cur_term.c to
account for the tgetent cache.

amend handling of the repeat_char capability
in EmitRange to avoid scope creep: translate the
character to the alternate character set when the alternate
character set is enabled, and do not use
repeat_char for characters past 255.

improve wide-character implementation of
myADDNSTR in frm_driver.c, which
was inconsistent with the normal implementation.

modify winnstr and winchnstr to
return error if the output pointer is null, as well as adding
a null pointer check of the window pointer for better
compatibility with other implementations.

modify setupterm to save original tty-modes
so that erasechar works as expected. Also modify
_nc_setupscreen to avoid redundant calls to get
original tty-modes.

modify wattr_set and wattr_get
to return ERR if win-parameter is null,
as documented.

correct order of initialization for traces in
use_env and use_tioctl versus first
_tracef calls.

correct parameters for copywin call in
_nc_Synchronize_Attributes

flush the standard output in _nc_flush for
the case where SP is zero, e.g., when called via
putp. This fixes a scenario where
“tput flash” did not work after changes in
20130112.

amend internal use of tputs to consistently
use the number of lines affected, e.g., for insert/delete
character operations. While merging terminfo source early in
1995, several descriptions used the
“*” proportional delay for these
operations, prompting a change in doupdate.

correct return-value of extended putwin.

double-width multibyte characters were not counted
properly in winsnstr and
wins_nwstr.

amend fix for _nc_ripoffline from 20091031 to
make test/ditto.c work in threaded
configuration.

modify _nc_viscbuf2 and
_tracecchar_t2 to trace wide-characters as a
whole rather than their multibyte equivalents.

minor fix in wadd_wchnstr to ensure that each
cell has nonzero width.

move PUTC_INIT calls next to
wcrtomb calls, to avoid carry-over of error
status when processing Unicode values which are not
mapped.

While reviewing user feedback, it became apparent that the
differences between reset (an alias for
tset) and “tput reset” were confusing:

one (tset)
updated the terminal modes, but used only part of the terminfo
capabilities for initialization, while

the other (tput)
used all of the terminal capabilities while neglecting the
terminal modes.

On further investigation, it turned out that the differences
were largely an accident due to the way those programs had
evolved.

This release eliminates the unnecessary differences, using the
same approach for tput's
init (initialization), reset and clear
operations as the separate
reset and
clear programs. Doing this does not change the
command-line options; existing scripts are unaffected.

These are the user-visible changes for the three programs
(tput, tset and clear):

add the terminal-mode parts of “reset” (aka tset) to the “tput
reset” command, making the two almost the same
except for window-size.

improve tput's check for
being called as “init” or “reset” to
allow for transformed names.

add “clear” as a possible link/alias to
tput.

amend changes for tput to
reset tty modes to “sane” if the program is run
as “reset”, like tset. Likewise, ensure that tset sends either reset- or
init-strings.

add -x option to clear/tput
to make the E3 extension optional

add functionality of
“tset -w” to tput, like the
“-c” feature this is not optional in
tput.

add options -T and -V to
clear command for
compatibility with tput.

drop long-obsolete “-n” option
from tset.

modify tset's assignment to
TERM in its output to reflect the name by which
the terminal description is found, rather than the primary
name. That was an unnecessary part from the initial
conversion of tset from
termcap to terminfo. The termcap library in 4.3BSD did this
to avoid using the short 2-character name

remove a restriction in tput's support for termcap names which
omitted capabilities normally not shown in termcap
translations

add usage message to clear
command

improve usage messages for tset and tput.

Other user-visible improvements and new features include:

modify tic/infocmp display of numeric values to use
hexadecimal when they are "close" to a power of two, making
the result more readable.

add “-W” option to tic/infocmp
to force long strings to wrap.

This is in addition to the
“-w” option which attempts to
fit capabilities into a given line-length.

If “-f” option splits line,
do not further split it with
“-W”.

Begin a new line when adding
“use=” after a wrapped line.

add “-q” option to infocmp to suppress the
“Reconstructed from” comment from
the header, and a corresponding option to tic to suppress all comments from the
“tic -I” output.

Sorted options in usage message for infocmp, to make it simpler to see unused
letters.

Updated usage message for tic, adding “-0”
option.

add infocmp/tic “-Q” option,
which allows one to dump the compiled form of the terminal
entry, in hexadecimal or base64:

A “b64:” prefix in the
TERMINFO variable tells the terminfo reader to
use base64 according to RFC-3548 as well as RFC-4648
url/filename-safe format.

A “hex:” prefix tells the
terminfo reader to accept hexadecimal data as generated by
“infocmp -0qQ1”.

Other less-visible improvements and new features include:

modify utility headers such as tic.h to make
it clearer which are externals that are used by tack.

add check in tic for some
syntax errors of delays, as well as use of proportional
delays for non-line capabilities.

add check in tic for
conflict between ritm, rmso,
rmul versus sgr0.

add check in _nc_parse_entry for invalid
entry name, setting the name to
“invalid” to avoid problems storing
entries.

improve _nc_tparm_analyze, using that to
extend the checks made by tic
for reporting inconsistencies between the expected number of
parameters for a capability and the actual.

remove tic warning about
“^?” in string capabilities, which
was marked as an extension; however all Unix implementations
support this and X/Open Curses does not address it. On the
other hand,
BSD termcap did not support this feature (until the
mid-1990s).

in _nc_infotocap, added a check to ensure
that terminfo “^?” is not written to
termcap.

modify sscanf calls in
_nc_infotocap for patterns
“%{number}%+%c” and
“%'char'%+%c” to check that the
final character is really “c”,
avoiding a case in icl6404 which cannot be converted to
termcap.

in _nc_tic_expand and
_nc_infotocap, improved string-length check when
deciding whether to use “^X” or
“\xxx” format for control
characters, to make the output of tic/infocmp
more predictable.

limited termcap “%d” width to 2
digits on input, and use “%2” in
preference to “%02” on output.

correct terminfo/termcap conversion of
“%02” and
“%03” into
“%2” and
“%3”; the result repeated the last
character.

This program iterates over the possible color
combinations, allocating or initializing color pairs. For
best results, choose screen-width dividing evenly into the
number of colors. e.g.,

32x64,32x128

256 colors

24x44,24x88

88 colors

32x64,24x128

16 colors

add extended_color program,
like the older color_set
program, but using the extended color functions, with and
without the SP-functions interface.

add picsmap program to fill
in some testing issues not met by dots, using this as the third example in a
comparison of the
ncurses versus slang libraries.

The program can directly read X bitmap and pixmap files,
displaying a picture. It can read other image files using
ImageMagick's convert program to translate the image
into text.

For 16-, 88- and 256-color terminal descriptions,
picsmap can load a palette
file which tells it which color palette entries to use. For
direct-colors, the terminal descriptions use the
RGB extension capability.

There are other new example programs and a few scripts:

add dots_xcurses program to
illustrate a different approach used for extended colors
which can be contrasted with dots_curses.

add list_keys program show
function keys for one or more terminal descriptions. It uses
ncurses's convention of
modifiers for special keys, based on xterm.

add padview program, to
compare pads with direct updates in the view program.

add sp_tinfo program to
exercise the SP-functions extension of the low-level terminfo
library.

add test-programs for termattrs and
term_attrs functions.

add test_sgr program to
exercise all combinations of the sgr capability.

add tput-initc script to
demonstrate how tput may be
used to initialize a color palette from a data file.

A variety of improvements were made to existing programs, both
new features as well as options added to make the set of programs
more consistent.

The ncurses program is the
largest; a proportionately large number of changes were made to
it:

modify a/A screens to make exiting on an escape character
depend on the start of keypad and timeout modes, to allow
better testing of function-keys.

add “t” toggle for
notimeout function.

modify layout of b/B screens to allow for additional
annotation on the right margin; some terminals with partial
support did not display well.

modify c/C screens to allow for extended color pairs.

add z/Z zoom feature to make extended color pairs
easier to test.

modify test-screens to take advantage of wide screens,
reducing the number of lines used for 88- and 256-colors.

modify “d” edit-color screen to
optionally read xterm color palette directly from terminal,
as well as handling KEY_RESIZE and
screen-repainting with control/L and control/R.

add examples to “F” screen for
WACS_D_PLUS and WACS_T_PLUS.

improve “g” screen, correcting
ifdef which made the legend not reflect changes to keypad-
and scroll-modes. Added check for return-value of
putwin.

make “s” test easier to
understand which subtests are available

add a corresponding “S”
wide-character overlap test-screen.

add “v” screen to show
baudrate and other values.

These changes were made to the other examples:

modify blue program to use
Unicode values for card-glyphs when available, as well as
improving the check for CP437 and CP850.

improve demo_menus program,
allowing mouse-click on the menu-headers to switch the active
menu. This requires a new extension option
O_MOUSE_MENU to tell the menu driver to put
mouse events which do not apply to the active menu back into
the queue so that the application can handle the event.

correct logic in demo_terminfo program for
“-f” option

modify ditto program to
allow $XTERM_PROG environment variable to
override "xterm" as the name of the program to run in the
threaded configuration.

add several options to the “dots”
test-programs.

modify filter program:

illustrate an alternative to getnstr, that
polls for input while updating a clock on the right margin
as well as responding to window size-changes.

adapt logic used in dialog
“--keep-tite” option for
filter program as the "-a"
option. When set, filter
attempts to suppress the alternate screen.

modify knight program to
provide the "slow" solution for small screens using
“R”, noting that Warnsdorf's method
is easily done with “a”.

attempts to improve the description of features which
users have found confusing

fills in overlooked descriptions of features which were
described in the NEWS
file but treated sketchily in manual pages.

In particular,

Since the underlying features for tset, tput, and clear have been better
integrated, the documentation now includes information on how
those tools evolved.

In addition to explaining the improved integration of the
tools, the manual pages made it easier to see how the tools
are similar and how they are different.

The addch manual page has additional
information on
portability and differences from other
implementations.

The discussion of color-pairs in the attributes
manual page is improved in its
history section.

The documentation of the chtype,
cchar_t types and the attribute values which can
be stored in those types, in particular the
history and
portability sections of the attributes manual
page, has been improved.

Some of the improvements are more subtle, relating to the way
the information is presented:

Made minor fixes to manpage NAME/SYNOPSIS
sections to consistently use rule that either all functions
which are prototyped in SYNOPSIS are listed in the
NAME section, or the manual-page name is the sole
item listed in the NAME section. The latter is used
to reduce clutter, e.g., for the top-level library manual
pages as well as for certain feature-pages such as SP-funcs and threading.

This release provides a new binary format for terminal
descriptions that use extended numeric capabilities. Applications
built with the wide-character ncursesw library can use
these extended numbers.

This includes utilities such as tic and infocmp, because (as noted in New features), the feature
relies upon an extension to the low-level tinfo
library.

A few software packagers use a configuration option of
ncurses which allows the
low-level tinfo library to be shared between the
high-level ncurses and ncursesw libraries.
This new feature was designed to work in that configuration
as well.

Other applications (i.e., using the 8-bit ncurses
library) which read the extended terminal descriptions see those
numeric capabilities set to the maximum value for a signed 16-bit
number.

Older versions of ncurses'
tic accept out-of-range numeric
capabilities, storing those as the maximum value for a signed
16-bit number. Other implementations of curses (mentioned in the
discussion of picsmap) give zero for these
out-of-range capabilities.

add --without-tack configure option to refine
--with-progs configure option. Normally
tack is built outside the
ncurses tree, but a few
packagers combine it during the build. If
term_entry.h is installed, there is no advantage
to in-tree builds.

adjust configure-script to define
HAVE_CURSES_DATA_BOOLNAMES symbol needed for
tack 1.08 when built in-tree.
Rather than relying upon internal "_nc_" functions,
tack now uses the boolean,
number and string capability name-arrays provided by
ncurses and SVr4 Unix curses.
It still uses term_entry.h for the definitions
of the extended capability arrays.

add dependency upon ncurses_cfg.h to tic's header-files; any program using
tic-library will have to
supply this file. Legacy tack
versions supply this file; ongoing tack development has dropped the
dependency upon tic-library
and new releases will not be affected.

Other changes to the configure-script and generated files
include

add configure options to disable checks for form, menu and
panel libraries so that ncurses-examples can be built with
non-SVr4 curses implementations.

add configure option --enable-opaque-curses
for ncurses library and similar options for the
other libraries.

add configure option --disable-wattr-macros
for use in cases where one wants to use the same headers for
ncurses5/ncurses6 development, by suppressing the
wattr* macros which differ due to the introduction
of extended colors

modify configure macro for shared-library rules to use
-Wl,-rpath rather than -rpath to
work around a bug in scons

improve ncurses-examples' configure script to define as
needed NCURSES_WIDECHAR for platforms where
_XOPEN_SOURCE_EXTENDED does not work. Also
modified the test program to ensure that if building with
ncurses, that the
cchar_t type is checked, since that is normally
(since 20111030)
ifdef'd depending on this test.

modify configure script to handle the case where
tic-library is renamed, but
the --with-debug option is used by itself
without normal or shared libraries

modify editing script which generates resulting.map to
work with the clang configuration on recent FreeBSD, which
gives an error on an empty "local" section.

improve configure check for setting the
WILDCARD_SYMS variable; on ppc64 the variable is
in the Data section rather than
Text.

correct result of configure option
--without-fallbacks, which caused FALLBACK_LIST
to be set to "no"

modify --with-pkg-config-libdir option to
make it possible to install “.pc” files even if
pkg-config is not found. Limit
this change, to suppress the actual install if it is not
overridden to a valid directory at install time.

disallow “no” as a possible value for
--with-shlib-version option, overlooked in
cleanup-changes for 20000708.

Many of the portability changes are implemented via the
configure script:

improve configure script's CF_CC_ENV_FLAGS
macro to allow for compiler wrappers such as ccache. This change moves only the
preprocessor, optimization and warning flags to
CPPFLAGS and CFLAGS, leaving the
residue in CC. That happens to work for
gcc's various
“model” options, but may require tuning for other
compilers.

modify ncurses-examples' configure script to use
pkg-config for the extra
form/menu/panel libraries, to be more consistent with the
handling of the curses/ncurses library.

change ncurses-examples to use attr_t vs
chtype to follow X/Open documentation more
closely since Solaris xpg4-curses uses different values for
WA_xxx vs A_xxx
that rely on attr_t being an unsigned short. Tru64 aka OSF1,
HPUX, AIX did as ncurses does,
equating the two sets.

modify several test programs to reflect that ncurses honors existing signal handlers in
initscr, while other implementations do not.

improve check for working poll function by
using posix_openpt as a fallback in case there
is no valid terminal on the standard input

modify ncurses-examples' configure script to check for
pthread dependency of
ncursest or ncursestw library when building
the ncurses examples, e.g., in
case weak symbols are used.

add checks in ncurses-examples' configure script for some
functions neither in 4.3BSD curses, nor based on X/Open
Curses:

modify a loop limit in firework.c to work around
absense of limit checks in some libraries.

fill the last row of a window with
“?” in firstlast if waddch does
not return ERR on the lower-right
corner.

build-fixes for the Portland Group (PGI) compilers

accept whitespace in sed expression for generating
expanded.c

modify configure check that g++ compiler warnings are
not used.

add configure check for -fPIC option needed for shared
libraries.

modify configure script for clang as used on FreeBSD, to
work around clang's differences in exit codes vs gcc.

fixes for configure/build using clang on OSX

do not redefine “inline” in
ncurses_cfg.h; this was originally to solve
a problem with gcc/g++, but is aggravated by clang's
misuse of symbols to pretend it is gcc.

add braces to configure script to prevent unwanted
addition of “-lstdc++” option to
the CXXLIBS symbol.

improve/update test-program used for checking
existence of stdc++ library.

if $CXXLIBS is set, the linkage test uses
that in addition to $LIBS.

fixes for OS/2:

use button instead of kbuf[0] in
EMX-specific part of lib_mouse.c

support building with libtool on OS/2

use stdc++ library with OS/2 kLIBC

clear configure script's cf_XOPEN_SOURCE
for OS/2, to work with its header files

add “newer” baudrate symbols to the baudrate function in the ncurses library as
well as to a corresponding table in tset.

modify ncurses-examples savescreen to work with AIX and HPUX.

define WIN32_LEAN_AND_MEAN for MinGW port,
making builds faster.

add a configure check for wcwidth versus the
ncurses line-drawing
characters, to use in special-casing systems such as Solaris.
Solaris, however, requires a special case that maps Unicode
line-drawing characters into the acsc string for non-Unicode
locales. Solaris also has a misconfigured wcwidth which marks
all of the line drawing characters as double-width.

the menus library, supporting a uniform but flexible
interface for menu programming.

the form library, supporting data collection through
on-screen forms.

ncurses's terminal database
is fully compatible with that used by SVr4 curses.

ncurses supports
user-defined capabilities which it can see, but which are
hidden from SVr4 curses applications using the
same terminal database.

It can be optionally configured to match the format
used in related systems such as AIX and Tru64.

Alternatively, ncurses
can be configured to use hashed databases rather than the
directory of files used by SVr4 curses.

The ncurses utilities have
options to allow you to filter terminfo entries for use with
less capable curses/terminfo versions such
as the HP/UX and AIX ports.

The ncurses package also has
many useful extensions over SVr4:

The API is 8-bit clean and base-level conformant with the
X/OPEN curses specification, XSI curses (that is, it
implements all BASE level features, and most EXTENDED
features). It includes many function calls not supported
under SVr4 curses (but portability of all calls is documented
so you can use the SVr4 subset only).

Unlike SVr3 curses, ncurses
can write to the rightmost-bottommost corner of the screen if
your terminal has an insert-character capability.

Ada95 and C++ bindings.

Support for mouse event reporting with X Window xterm and
FreeBSD and OS/2 console windows.

Extended mouse support via Alessandro Rubini's gpm
package.

The function wresize allows you to resize
windows, preserving their data.

The function use_default_colors allows you to
use the terminal's default colors for the default color pair,
achieving the effect of transparent colors.

The functions keyok and
define_key allow you to better control the use
of function keys, e.g., disabling the ncurses KEY_MOUSE, or by defining more
than one control sequence to map to a given key code.

Support for 256-color terminals, such as modern xterm.

Support for 16-color terminals, such as aixterm
and modern xterm.

Better cursor-movement optimization. The package now
features a cursor-local-movement computation more efficient
than either BSD's or System V's.

Super hardware scrolling support. The screen-update code
incorporates a novel, simple, and cheap algorithm that
enables it to make optimal use of hardware scrolling,
line-insertion, and line-deletion for screen-line movements.
This algorithm is more powerful than the 4.4BSD curses
quickch routine.

Real support for terminals with the magic-cookie glitch.
The screen-update code will refrain from drawing a highlight
if the magic- cookie unattributed spaces required just before
the beginning and after the end would step on a non-space
character. It will automatically shift highlight boundaries
when doing so would make it possible to draw the highlight
without changing the visual appearance of the screen.

It is possible to generate the library with a list of
pre-loaded fallback entries linked to it so that it can serve
those terminal types even when no terminfo tree or termcap
file is accessible (this may be useful for support of
screen-oriented programs that must run in single-user
mode).

The
tic/captoinfo
utility provided with ncurses
has the ability to translate many termcaps from the XENIX,
IBM and AT&T extension sets.

The ncurses library and
utilities will automatically read terminfo entries from
$HOME/.terminfo if it exists, and compile to that directory
if it exists and the user has no write access to the system
directory. This feature makes it easier for users to have
personal terminfo entries without giving up access to the
system terminfo directory.

You may specify a path of directories to search for
compiled descriptions with the environment variable
TERMINFO_DIRS (this generalizes the feature provided by
TERMINFO under stock System V.)

In terminfo source files, use capabilities may refer not
just to other entries in the same source file (as in System
V) but also to compiled entries in either the system terminfo
directory or the user's $HOME/.terminfo directory.

The table-of-entries utility
toe makes it easy for users to see exactly what
terminal types are available on the system.

The library meets the XSI requirement that every macro
entry point have a corresponding function which may be linked
(and will be prototype-checked) if the macro definition is
disabled with #undef.

Zeyd Ben-Halim started ncurses
from a previous package pcurses, written by Pavel Curtis. Eric S.
Raymond continued development. Jürgen Pfeifer wrote most of
the form and menu libraries. Ongoing development work is done by
Thomas Dickey.
Thomas Dickey also acts as the maintainer for the Free Software
Foundation, which holds the copyright
on ncurses.

The distribution provides a newer version of the
terminfo-format terminal description file once maintained by
Eric
Raymond . Unlike the older version, the termcap and
terminfo data are provided in the same file, which also provides
several user-definable extensions beyond the X/Open
specification.